Land degradation is one of the serious environmental problems that can lead to poverty, and is especially prominent in eco-fragile areas in developing countries and increases the risk of environmental safety. North He...Land degradation is one of the serious environmental problems that can lead to poverty, and is especially prominent in eco-fragile areas in developing countries and increases the risk of environmental safety. North Hebei Province belongs to an ecologically fragile region in North China, which has great impact on the eco-safety of Beijing and Tianjin. Using Landsat TM data and GIS, this paper evaluates land degradation in North Hebei province of China from the the 1960′s to 1987 and 2000. Land use/cover change pattern from 1987 to 2000, its regional difference and forest change characteristics will also be analyzed; soil erosion intensity and arable land suitability were also evaluated. Results revealed that land use/cover pattern in this study area did not change greatly from 1987 to 2000. The structure and function of regional land ecosystem was at a level of local improvement and integral deterioration. Land above medium soil erosion intensity reached 21 percent, which was also the area with a serious soil erosion and land degradation problem. Soil erosion and land degradation intensity of grassland was the biggest. For the present arable land, the proportion of high suitability was 13 percent.展开更多
The source of ore\|forming materials has long been a controversial focus both in metallogenic theory and in ore\|searching practice. This study deals with the helium and argon isotopic characteristics of pyrites from ...The source of ore\|forming materials has long been a controversial focus both in metallogenic theory and in ore\|searching practice. This study deals with the helium and argon isotopic characteristics of pyrites from 11 gold deposits and some country rocks in the gold mineralization\|concentrated areas within the three mantle\|branch structures in the region of North Hebei Province. It is indicated that \{\}\+3He/\+4He ratios in the gold deposits are within the range of \{0.93×10\+\{-6\}\}-\{7.3×10\+\{-6\}\}, with an average of \{3.55\} ×10\+\{-6\}; R/Ra=\{0.66\}-\{4.93\}, averaging \{2.53\}; \{\{\}\+\{40\}Ar/\+\{39\}Ar\} ratios vary between 426 and 2073, with the average value of \{\}\+\{40\}Ar being \{8.32\}; and the average of \{\}\+4He/\{\}\+\{40\}Ar ratios is 2.17. \{\}\+3He/ \{\}\+4He ratios in gneiss and granite in the periphery of the mining district are within the range of \{0.001×10\+\{-6\}\}-\{0.55×10\+\{-6\}\}, reflecting significant differences in their sources. \{\}\+3He and \{\}\+4He fall near the mantle, as is shown in the He concentration diagram. Studies have shown that the ore\|forming materials in this region should come from the deep interior of the Earth. With the multi\|stage evolution of mantle plume, ore\|forming fluids in the deep interior were moving upwards to shallow levels (crust). Under such circumstances, there would be inevitably occur crust/mantle fluid mixing, so their noble gas isotopic characteristics are intermediate between the mantle and the crust.展开更多
Experiments were carried out in 1994 - 1998 to study crop rotation and its effects on crop water consumption characteristics of field with sandy chestnut soil in the Plateau of north Hebei Province. Five crops includi...Experiments were carried out in 1994 - 1998 to study crop rotation and its effects on crop water consumption characteristics of field with sandy chestnut soil in the Plateau of north Hebei Province. Five crops including spring wheat, oat, pea, flax and potato were examined. There was little difference in field water consumption among the crops during the growing season. WUE varied significantly in a range of 1. 347 -11.177kg · ha-1 · mm-1 among crops and 11.44% - 46.66% among previous crops. It was pointed out that the land equivalent ratio (LER) can be used as an index to evaluate the biological effects of crop rotation comprehensively. The 2-4 year crop rotation patterns with higher LER were estimated in the paper.展开更多
In West Liaoning-North Hebei, the Tiaojishan Formation volcanic rocks are developed and many isotopic ages with a very wide age range were obtained in them as well. These different ages have direct influence on confir...In West Liaoning-North Hebei, the Tiaojishan Formation volcanic rocks are developed and many isotopic ages with a very wide age range were obtained in them as well. These different ages have direct influence on confirming and interpreting the related geological issues in West Liaoning-North Hebei and have restricted the study of geological problems related. In the field, the Tiaojishan Formation and the overlying Tuchengzi Formation are in parallel unconformable contact. By systematical sampling and dating of LA-ICP-MS in the Tiaojishan Formation (especially in the upper part) in Luanping, Chengde basins of Northern Hebei Province and in Lingyuan, Jinlingsi-Yangshan basins of Western Liaoning Province, combined with the dating data obtained by previous researchers, results indicate that the upper boundary age of the Tiaojishan Formation is from 156 to 153 Ma, and the lower boundary age of the Tiaojishan Formation is about 165 Ma, the Tiaojishan Formation was formed from the late of middle Jurassic to late Jurassic Epoch.展开更多
Drought monitoring is the base for drought coping and adaptation. Xingtai is located in North China's key winter wheat production areas where drought is severe and frequent. The rainfall during winter wheat growing s...Drought monitoring is the base for drought coping and adaptation. Xingtai is located in North China's key winter wheat production areas where drought is severe and frequent. The rainfall during winter wheat growing season is just about 1/3 of total demand. Xingtai has typical mountainous, hilly and plain agricultural zones, compound rain-fed and irrigated farming patterns. The winter wheat irrigation has heavily depended on overdraw of groundwater in recent decades. In the study, the MODIS (Moderate-Resolution Imaging Spectroradiometer) images taken at the key winter wheat growing season (Mar. to May) in normal rainfall year (2006) were selected, extracted NDVI (Normalized Difference Vegetation Index) and LST (Land Surface Temperature) data, calculated TVDI (Temperature and Vegetation Drought Index), classified and mapped winter wheat drought intensity. Further, based on TVDI, a CDRA (Comprehensive Drought Risk Assessment) model for winter wheat drought disaster risk assessment was constructed and zoning was made. Verified by winter wheat yield, the risk zoning by CDRA is consistent with actual crop failure space. This method can be used in drought risk management.展开更多
基金The authors would like to greatly thank the National Natural Science Foundation of China(No.40171001 and No.40571117)the grant of the Knowledge Innovation Program of the Chinese Academy of Sciences(approved # KZCX3-SW-338)National High Technology Research and Development Program of China(No:2003AA131170)which founded this research.
文摘Land degradation is one of the serious environmental problems that can lead to poverty, and is especially prominent in eco-fragile areas in developing countries and increases the risk of environmental safety. North Hebei Province belongs to an ecologically fragile region in North China, which has great impact on the eco-safety of Beijing and Tianjin. Using Landsat TM data and GIS, this paper evaluates land degradation in North Hebei province of China from the the 1960′s to 1987 and 2000. Land use/cover change pattern from 1987 to 2000, its regional difference and forest change characteristics will also be analyzed; soil erosion intensity and arable land suitability were also evaluated. Results revealed that land use/cover pattern in this study area did not change greatly from 1987 to 2000. The structure and function of regional land ecosystem was at a level of local improvement and integral deterioration. Land above medium soil erosion intensity reached 21 percent, which was also the area with a serious soil erosion and land degradation problem. Soil erosion and land degradation intensity of grassland was the biggest. For the present arable land, the proportion of high suitability was 13 percent.
文摘The source of ore\|forming materials has long been a controversial focus both in metallogenic theory and in ore\|searching practice. This study deals with the helium and argon isotopic characteristics of pyrites from 11 gold deposits and some country rocks in the gold mineralization\|concentrated areas within the three mantle\|branch structures in the region of North Hebei Province. It is indicated that \{\}\+3He/\+4He ratios in the gold deposits are within the range of \{0.93×10\+\{-6\}\}-\{7.3×10\+\{-6\}\}, with an average of \{3.55\} ×10\+\{-6\}; R/Ra=\{0.66\}-\{4.93\}, averaging \{2.53\}; \{\{\}\+\{40\}Ar/\+\{39\}Ar\} ratios vary between 426 and 2073, with the average value of \{\}\+\{40\}Ar being \{8.32\}; and the average of \{\}\+4He/\{\}\+\{40\}Ar ratios is 2.17. \{\}\+3He/ \{\}\+4He ratios in gneiss and granite in the periphery of the mining district are within the range of \{0.001×10\+\{-6\}\}-\{0.55×10\+\{-6\}\}, reflecting significant differences in their sources. \{\}\+3He and \{\}\+4He fall near the mantle, as is shown in the He concentration diagram. Studies have shown that the ore\|forming materials in this region should come from the deep interior of the Earth. With the multi\|stage evolution of mantle plume, ore\|forming fluids in the deep interior were moving upwards to shallow levels (crust). Under such circumstances, there would be inevitably occur crust/mantle fluid mixing, so their noble gas isotopic characteristics are intermediate between the mantle and the crust.
文摘Experiments were carried out in 1994 - 1998 to study crop rotation and its effects on crop water consumption characteristics of field with sandy chestnut soil in the Plateau of north Hebei Province. Five crops including spring wheat, oat, pea, flax and potato were examined. There was little difference in field water consumption among the crops during the growing season. WUE varied significantly in a range of 1. 347 -11.177kg · ha-1 · mm-1 among crops and 11.44% - 46.66% among previous crops. It was pointed out that the land equivalent ratio (LER) can be used as an index to evaluate the biological effects of crop rotation comprehensively. The 2-4 year crop rotation patterns with higher LER were estimated in the paper.
基金"the 111 Plan of University and College (B07039)the Key Project of the National Natural Science Foundation of China (Grant No. 90714010)
文摘In West Liaoning-North Hebei, the Tiaojishan Formation volcanic rocks are developed and many isotopic ages with a very wide age range were obtained in them as well. These different ages have direct influence on confirming and interpreting the related geological issues in West Liaoning-North Hebei and have restricted the study of geological problems related. In the field, the Tiaojishan Formation and the overlying Tuchengzi Formation are in parallel unconformable contact. By systematical sampling and dating of LA-ICP-MS in the Tiaojishan Formation (especially in the upper part) in Luanping, Chengde basins of Northern Hebei Province and in Lingyuan, Jinlingsi-Yangshan basins of Western Liaoning Province, combined with the dating data obtained by previous researchers, results indicate that the upper boundary age of the Tiaojishan Formation is from 156 to 153 Ma, and the lower boundary age of the Tiaojishan Formation is about 165 Ma, the Tiaojishan Formation was formed from the late of middle Jurassic to late Jurassic Epoch.
基金The study was supported by the National Natural Science Foundation of China [No.46171501 ].
文摘Drought monitoring is the base for drought coping and adaptation. Xingtai is located in North China's key winter wheat production areas where drought is severe and frequent. The rainfall during winter wheat growing season is just about 1/3 of total demand. Xingtai has typical mountainous, hilly and plain agricultural zones, compound rain-fed and irrigated farming patterns. The winter wheat irrigation has heavily depended on overdraw of groundwater in recent decades. In the study, the MODIS (Moderate-Resolution Imaging Spectroradiometer) images taken at the key winter wheat growing season (Mar. to May) in normal rainfall year (2006) were selected, extracted NDVI (Normalized Difference Vegetation Index) and LST (Land Surface Temperature) data, calculated TVDI (Temperature and Vegetation Drought Index), classified and mapped winter wheat drought intensity. Further, based on TVDI, a CDRA (Comprehensive Drought Risk Assessment) model for winter wheat drought disaster risk assessment was constructed and zoning was made. Verified by winter wheat yield, the risk zoning by CDRA is consistent with actual crop failure space. This method can be used in drought risk management.